Mechanical stoker



June 20, 1933. w. D. BURTON MECHANICAL STOKER Filed May 27, 1929 Y Tnve rah/3f can, ffm@ waffm M Patented .lune 20, 1933 UNrrED STATES WARREN DEAN BURTON,

INC., 0F 'CICERQ PATENT ori-'ica connus-nonnen. rumors MECHANICAL s'roxm.

Application tiled Hay 27,

The present invention relates to improvements innneclianical stokers, and is particularly applicable to stokers of the underfeed t e.

yIn one form of undei'feed stokers, coal is fed by a power driven screw conveyor rom a hopper through a conveyor casing or duct into the bottom of a retort where it is consumed. The coal supplied to the hopper often contains foreign objects, such as pieces of iron, steel or rock, Frequently, these objects form obstructions at the outlet of the hopper, thereby clogging the apparatus. In this event, if thedrive for the screw conveyor is not disconnected, se-

rious damage to the apparatus may result.

To avoid the possibility of such damage, it is common to interpose he drive for the screw when subjected to of the force required in normal operation, and which can be readily replaced.

If an obstruction in the hopper causes a break down in the operation, obviously, the obstruction must be removed and a new shear member must be provided before the operation can be started again. This involves inconvenience and often a considerable loss of time.

' the present invenprovision of a novel safety cut-out mechanism which will automatically disengage the power drive for the conveyor 1 an obstruction causes aforee substantially in excess of the normal force to be applied to the conveyor.

In operation, the conveyor is subjected to end thrust. An important object of the ina new an improved safety cut-out mechanism which comprises means adapted to resist the normal end thrust but to permit endwise movemen of the conveyor in instances of excessive en thrust, and means operable upon such endwise movement of the conveyor to disengagc the power drive for the conveyor until the excessive A more specific vision in combination with a safey cut-out mechanism of the foregoing character of a t tom of the retort is a suitable 1929. Serial N0. $66,153.

removable closure in the hopper adj aeent the conveyor outlet for permitting obstructions to be readil and quickly removed removing al of the coal from the hopper.

Further' objects and advantages will become apparent as the description lroceeds.'

In the accompan ing drawing, igure 1 is a vertical, longitu inal sectional f a stoker embodying the features of my invention.

Fig. 2 is a sectional view taken along line 2-2 of Fig. 1.

Fig. 3 is an enlarged fragmentary sectional view of the drive and safety cut-out mhanism for the conveyor.

Fig. 4 is a transverse sectional view taken along line of Fig. 3.

Fig. 5 is an end view of the clutch taken alon line 5-5 of Fig. 3.

W ile the invention` is susceptible of various modifications and alternative constructions, I have shown'n` he drawin and will herein describe in detai the pre erred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications falling within the spirlt and scope of the invention as'expresse in the appended claims.

Referring more specifically to the drawing, the exemplary embodiment of the invention comprises an upwardly opening retort 10 of standard construction having openings 11 about the upper ed an inlet duct 12 at the bottom. duct 12 is connected through a conveyor duct or casing 13 preferably cylindrical in form to the base 14 of a hopper 15 into which coa d is supplied. Extending through the base 14 13 into the retort 10 for conper 15 into the bot conveyor screw 16 having a longitudinal shaft 17.

The end of the shaft 17 extends out of the hopper base 14 for connection to a suitable power drive. In the present instance, this ower drive comprises j 18 adapted to e connected to a suitable-source of power (not shown) and keyed to a sleeve 19 journaled in bearings 2O and and the casmg veying coal from 21 in opposite side.

the s a -191sasha 2 miam 22. The latter whenthe latter is operatin under the moet severe no condtions. e event of an obstruction in the hop r base 14, the end rusten econveyor 1. isgreatly increased,

to move the latter endwise against the spring 31. If the end thr ceeds a predetermined amount, the in 27 moved out of the notches 28, t ereby thefEower drive for the conveyor walls -of a suitable housing is rigidl secured hopper glee 14, with suitable lugs 23 bolted arms 24 projecting ndfrotatably ft 25.' The inner end 25 is suitably'connected to the by a coupling- 26. The

the opposite ends of which are adapted engage in two diametricall 28h formed in rom the base. disposed in the sleeve of theV shaft shaft 17, Ils

need not e operation is disuse of excessive load en ,.the

the event of an excessive load the conve or should fail to move endwise, the a torque\ pin 2; would still operate as a shear pin, rmined safety torfue. thereby to the parte.

eans is provided for yiel ly ho ding the pin 27 in the notches 28 to complete the drive connection for the conveyor 16.l Preferabl this means is a spring unit actin on aft 25, and tending to move or old the latter together with the the right o positeto th thi-.ust

31 disposed between the as 29 is provided on h a hub'32embrcin her lend of the forms r lee4 14 is qpggral 34 or a disk 35-on the b one end of the sprin the outer sleeve 30, the en 35 is turned out to form a spaced from to pin Secured, as the adjacent wall of hase and the bottom bracket 41. i hopper base 14 casing 13 is a 3 for permitting the -le` Y is opening norma y Elate 44 formed rac et 42. Formed end turned flange 37 2 the spring 31 un. against a o a s coal from the hop e entrance o an obstruction binds or e sp 31 tends tov 120 to the lill'izt only when 6in-e notse arated permise; le extent. e selfcontained spring unit thus takes up the reaction of the spring except when the end thrust on the conveyor exceeds the spring urge the conveyor 16 the disk 35 and the Han e 3 to the fullest per base at e tion would take from filling the space so 1:20

created-by the defiector Harige 45.l It will be' ev'idet that by reason of the foregoing construction, the obstruction can be readily and quickly removed without removing all of the coal from the hopper, and that the stoker thereupon will be put automatically into operation Iwithout any considerable loss of time.

I claim as myinvention: f

1. A stoker comprising, in combination, a hopper, a discharge duct opening from the rlower end of said hopper, an axial thrust rotary feeding means extending through said hopper into said duct, said means having a limited vaxial movement, means for driving said feeding means, said last mentioned means including a clutch adapted to be opened and closed automatically upon axial movement of said feeding means in'oppositedirections, and spring. means acting on said feeding means in a direction to close said clutch.-

.2. A Stoker comprising, in combination, a container, a rotary screw conveyor in said container, said conveyor having a limited axial movement, means for rotating said conveyor, said means including a clutch adapted to be opened and closed automatically upon axial movement of said conveyor in opposite directions, and yielding means acting on said conveyor in a direction to close said clutch. l

3. A Stoker comprising, in combination, a container, a rotary screw conveyor in said container, said conveyor having a shaft extending from said container, means for driving said shaft, said means including a clutch adapted to be opened and closed upon endwise movement of said conveyor in opposite directions, and a self-contained spring unit tending to move said conveyor endwise for a limited distance in a direction to maintain said clutch in closed position.

4. In a Stoker, in combination, a shaft, a fixed abutment, an inner concentric sleeve rigidly secured to said shaft, and having a spring seat at one end, an outer concentric sleeve having a spring seat opposed to said first 'mentioned seat and engaging said abutment, spring means interposed between said sleeves and abutting at opposite ends against said seats, said spring means tending to effect a relative axial movement between said sleeves, and means for limiting the extent of said moveme t.

5. In a Stoker, in combination, a shaft, an abutment, an inner spring retainer rigidly secured to said shaft, arid having a spring seat at one end, an outer spring retainer having a spring seat opposed to said first mentioned seat and engaging said abutment, a coil lcompression spring interposed between said retainers and abutting at opposite ends against said seats, and guide means connecting said retainers for limited relative movea clutch operable to open and close upon axial movement of said last mentioned shaft in opposite directions, means connecting said shafts for joint movement, and a spring compression unit mounted between said container and said transmission and acting on said last mentioned shaft in a clutch.

7. In a stoker, i-n combination, a casing, a sleeve journaledl insaid casing, means for rotating said sleeve, a shaft extending r0- tatably and slidably through said sleeve, one end of said sleeve being formed with a pair of diainetrically opposed notches, `a shear pin extending diametrically through saidv shaft and adapted to engage in said notches to effect a driving connection between said sleeve and said shaft, and spring means tending to hold said pin in said notches.

8. In a stoker, in combination, a casing, a sleeve journaled in said casing, means for rotating said sleeve, a shaft extending rotatably and slidably through said sleeve, one end of said sleeve being formed with a recess, a projection on said shaft adapted to engage in said recess to effect a driving connection between said sleeve and said shaft, and yielding means tending to maintain said projection in said recess.

9. In a Stoker, in combination, a casing, a sleevejournaled in said casing, means for rotating said sleeve, a shaft extending rotatably and slidably through said sleeve,l one endv of said sleeve being formed with a recess, a projection on said shaft adapted to engage in said recess to effect a driving connection between said sleeve and said shaft, and spring means acting on said shaft to move the latter endwise in a direction to maintain said projection in said notch.

10. In a stoker, in combination, a casing, a sleeve journaled in said casing, means for rotating said sleeve, a shaft rotatable in Arsaid sleeve, said shaft and said sleeve being relatively slidable, one end of said sleeve being formed with a recess having a side face inclined to the plane of said end, a projection on said shaft adapted to engage in said recess to effect a driving connection between said sleeve and said shaft, and yielding means tending to maintain said projection in said recess, said face being effective when the rotative force applied by said sleeve to said shaft exceeds a predetermined value to foi-ce said projection out of said recess against the action of said yielding means.

11. A stoker comprising, in combination,

direction to close said *30 a hopper having a discharge outlet, a rotary screw conveyor in said hopper for discharging fuel through said outlet, a drive sleeve, said conveyor having a shaft extendin throu h said drive sleeve, said sleeve an said s aft having relative axial movement, one end of'said sleeve being formed with a recess, a project-ion on said shaft adapted to engage in said recess to eiect a driving connection betweenvsaid sleeve and said shaft, yielding means tending to maintain said projection in said recess, said hopper being formed with an opening adjacent said outlet, and a removable closure for said opening.

12. A stokcr comprising, in'combination, a hopper, a lateral duct opening from the bottom of said hopper, a retort connected to the discharge end of saidduct, a conveyer screw extending throughthe bottom of said hopper and through said duct into said retort, said conveyerhaving a limited axial movement, means for driving said conveyer, said last mentioned means including a clutch adapted to be opened and closed automatically upon axial movement of said conveyer in opposite directions, and spring means operatively mounted axially of said conveyer screw and normally acting' thereon to move the conveyer in a direction to close said clutch.

13. A Stoker comprising, in combination, a hopper, a lateral duct opening from the bottom of said hopper, a retort connected to the discharge end of said duct, a conveyer.

screw extending through the bottom of. said hopper and longitudinally of said duct into said-retort and means for driving said con veyer screw, said means including a clutch normally spring pressed into closed position and adapted to open automatically when the rotative force applied by said driving means to the conveyer screw exceeds a predetermined value, one element of said clutch secured to said conveyer screw for movement therewith, said clutch being restored to driving relation with said conveyer as an incident to the reduction of resistance to rotative movement thereof.

14. A Stoker comprising, in combination, a

hopper, a lateral duct opening from the bot- I tom of said hopper, a rotary screw conveyer extending through .the bottom of said hopper and into said duct and means for driving said conveyer including a driving member, spring means `normally acting to move said conveyer endwise relatively to said member and interengaging means on said membenand said conveyer effective to provide a driving connection therebetweemsaid spring means acting to move said conveyer to effect a driv- A ing engagement withsaid member.

15. An underfeed stoker comprising; in combination, a vertical fuel container, a orizontal duct opening laterally from the lower end of said container, a rotary screw conveyor extending from saidcontainer into sald duct for discharging fuel thereto, said container having an opening at its 'uncture with said duct, a removable closure or said opening, said opening affording convenient access to the interior of said .container for removing obstructions that may lodge between said conveyor and said closure and tend to interfere with the rotation of said conveyor, and drive means for said conveyor, said -drive means comprising a shaft operatively connected to said conveyor, a sleeve on said shaft, said shaft and said sleeve being relatively axially movable, means for rotatin said sleeve, coacting clutch elements on sai shaft and said sleeve movable into and out of engagement upon relative axial movement of said shaft and sleeve in opposite directions, and spring means tending to hold said elements in operative en agement, said elements being adapted to be isengaged automatically upon relative movement between said shaft and said sleeve in response to a load exceeding a predetermined value.

In testimony whereof, I have hereunto a-ffixed my signature.

WARREN DEAN BURTON. 

